Cambridge, MA planting zone & frost dates
Cambridge is in USDA hardiness zone 6b. The last spring frost usually comes around April 4 and the first fall frost around November 9, for a growing season of about 218 days.
Planting calendar for Cambridge
Dates are counted from the average last spring frost (April 4) using the typical timing recommended by U.S. extension services. Warm-season crops go out only after the danger of frost has passed and the soil has warmed.
| Crop | When |
|---|---|
| Tomatoes | Start seeds indoors: Feb 7 – Feb 21 Transplant outdoors: Apr 11 – Apr 18 |
| Peppers | Start seeds indoors: Jan 24 – Feb 7 Transplant outdoors: Apr 18 – Apr 25 |
| Eggplant | Start seeds indoors: Jan 24 – Feb 7 Transplant outdoors: Apr 18 – Apr 25 |
| Broccoli | Start seeds indoors: Jan 24 – Feb 7 Transplant outdoors: Mar 7 – Mar 21 |
| Cabbage | Start seeds indoors: Jan 24 – Feb 7 Transplant outdoors: Mar 7 – Mar 21 |
| Onions (sets) | Plant outdoors: Mar 7 – Mar 21 |
| Peas | Sow outdoors: Feb 21 – Mar 7 |
| Spinach | Sow outdoors: Feb 21 – Mar 7 |
| Lettuce | Sow outdoors: Mar 7 – Mar 21 |
| Carrots | Sow outdoors: Mar 7 – Mar 21 |
| Potatoes | Plant outdoors: Mar 7 – Mar 21 |
| Beans | Sow outdoors: Apr 11 – Apr 18 |
| Sweet corn | Sow outdoors: Apr 11 – Apr 18 |
| Cucumbers | Sow outdoors: Apr 11 – Apr 18 |
| Squash & zucchini | Sow outdoors: Apr 11 – Apr 18 |
| Basil | Start seeds indoors: Feb 21 – Mar 7 Transplant outdoors: Apr 11 – Apr 18 |
Fall garden: cool-season crops like lettuce, spinach and kale can be sown again around Sep 14 (8 weeks before the average first fall frost on Nov 9).
Useful for zone 6b gardens
- Seed starting kit with dome — to start seeds indoors before the last frost
- LED grow light for seedlings — stops leggy seedlings
- Frost cloth / plant covers — for late spring and early fall frosts
- Soil thermometer — warm-season crops need soil above 60°F
- Cold frame / mini greenhouse — adds weeks to a short season
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Frost risk in detail
| 90% chance | 50% chance | 10% chance | |
|---|---|---|---|
| Last 32°F frost in spring is after | Mar 25 | Apr 4 | Apr 17 |
| First 32°F frost in fall is before | Nov 22 | Nov 9 | Oct 29 |
How to read it: in spring there is a 10% chance of a frost after April 17, so that is a safe date for tender plants. In fall there is a 10% chance of frost before October 29. A hard freeze (28°F) usually ends around March 28.
Hardiness zone by ZIP code in Cambridge
- 02138 zone 6b
- 02139 zone 6b
- 02140 zone 6b
- 02141 zone 7a
- 02142 zone 7a
- 02238 zone 6b
Nearby cities
- Somerville zone 7a, last frost Apr 4
- Winter Hill zone 7a, last frost Apr 4
- Allston zone 6b, last frost Apr 19
- East Cambridge zone 7a, last frost Apr 4
- Back Bay zone 7a, last frost Apr 19
- Mission Hill zone 6b, last frost Apr 19
- Medford zone 6b, last frost Apr 4
- Charlestown zone 7a, last frost Apr 4
Questions
What growing zone is Cambridge, MA?
Cambridge is in USDA Plant Hardiness Zone 6b (average extreme winter low -5°F to 0°F), according to the USDA 2023 map. Some ZIP codes of the city fall in zone 7a.
When is the last frost in Cambridge?
The average last spring frost (32°F) in Cambridge is April 4. There is still a 10% chance of frost until April 17.
When can I plant tomatoes in Cambridge?
Transplant tomatoes outdoors 1–2 weeks after the average last frost: around Apr 11 – Apr 18. Start seeds indoors 6–8 weeks before the last frost.
Frost dates: NOAA U.S. Climate Normals 1991–2020, station Boston Logan Intl Ap, MA (USW00014739), 8.0 km (5.0 mi) from the city center, elevation 4 m, based on 28 years of records. Hardiness zone: USDA Plant Hardiness Zone Map 2023 for the ZIP code nearest to the city center. Microclimates (valleys, hills, cities, coasts) can be warmer or colder: check the local forecast before planting. How we calculate the data.